1. Field of the Invention
The invention relates to a dual mass clutch flywheel which is able to rotate about a main axis of rotation and comprises two masses and a torsional vibration damper, which is capable of damping rotary vibrations by means of a spring damper device acting between the two masses. For this purpose the spring-damper device has a spring system and a damper system. In a load-free condition, both masses are able to rotate in an idling position about the main axis of rotation, and in a loaded condition are able to rotate against the spring-damper device about a main axis of rotation, offset by a relative angle to each other. Here the spring system has springs which are guided by hold-down devices radially to the main axis of rotation, which devices are connected to each other by means of a fly ring, wherein the fly ring is freely able to follow the springs at least over a small relative idling angle around the idling position.
2. Description of the Related Art
A multiplicity of dual mass clutch flywheels is known from the state of the art, in which two masses are connected to a torsional vibration damper whose springs are guided by sliding shoes which are supported radially on the outside of a component of one of the masses. An example of this is disclosed in DE 197 00 851 A1. Whilst the friction of these sliding shoes on the corresponding mass results in a damping which is desirable in itself, this is highly speed dependent, which in turn leads to major matching problems since such dual mass clutch flywheels are operated at greatly varying speeds. For this reason there are dual mass clutch flywheels in which the sliding shoes are connected to each other by a fly ring, which is disclosed in DE 100 28 268 A1. Nevertheless the sliding shoes still rub against one of the two masses, although a dependency on centrifugal force is prevented by the fly ring connecting the sliding shoes, so that the fly ring which is rigidly connected to the sliding shoes correspondingly rubs against this mass and is not free.
On the other hand, EP 0 421 965 A1 discloses a free fly ring which is mounted freely rotatably between the two masses and engage in the springs by means of noses, which springs in turn rest on one of the two masses, and therefore rub against it. To this extent a friction or damping dependent on centrifugal force is prevented by the fly ring in this arrangement.
For example, a non-generic hydrodynamic power transmitter is also known from DE 197 51 752 A1, which transmitter comprises a torsional vibration damper with a spring-damper device, wherein the spring-damper device comprises a spring system with a flyer which supports two helical spring parts against centrifugal forces. This arrangement, however, is a dual mass clutch flywheel with a frictionally acting damper part which does not become active between masses spring mounted by a spring part, but instead idling damping takes place due to the intrinsic characteristics of the hydrodynamic power transmitter. The situation is different in the generic arrangements according to DE 100 28 268 A1 or EP 0 421 965 A1, in which idling disengaging is an essential element and can only be realized at considerable cost and incurring other disadvantages.